Thick film conductors are commonly used in the electronics industry and are of increasing importance as trends progress towards smaller and smaller circuits. Thick film conductors can be formed, for example, by screen printing a thick film conductive ink that is formulated with a powdered base metal onto a non-conductive substrate such as 96% alumina The thick film conductive ink is then dried to volatilize vehicle constituents and fired to sinter or fuse the powdered base metal and other remaining constituents to bond the film to the substrate.
Previously, thick film conductive inks typically included precious metals such as gold, silver, platinum, and palladium as the powdered base metal. More recently, in efforts to reduce cost, thick film conductive inks containing copper powder have been introduced into the market. Such thick film conductive inks also contain glass as an adhesion promoter that becomes soft when heated to temperatures suitable for sintering the copper powder, e.g., 675° C. or greater, to fuse the thick film conductor to the substrate. Unfortunately, glass is more resistive and can contain lead which is environmentally objectionable.
Accordingly, it is desirable to provide thick film conductive inks without glass for electronic devices, for example, to eliminate the presence of lead in the film or make the ink less resistive, methods for making electronic devices using such thick film conductive inks, and electronic devices fabricated by such methods. Moreover, it is desirable to provide thick film conductive inks with reduced cost for electronic devices, methods for making electronic devices using such thick film conductive inks, and electronic devices fabricated by such methods. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.